What Soil Holds the Most Plant Available Water

Water is essential for the growth of plants. Therefore, it is important to know which soil type is capable of holding the most plant available water. Plant available water refers to the water that is held in soil but is also available for plants to use. The capacity of a soil type to hold plant available water is mainly influenced by its texture, structure, and organic matter content.

Texture of Soil

Soil texture refers to the relative proportion of sand, silt, and clay particles that make up a specific soil. Sand particles are the largest and the most coarse-textured. Silt particles are much smaller than sand particles but are still visible. Clay particles are the smallest and are invisible to the naked eye. When we talk about soil texture, we refer to the combination of these three particles.

Generally, soil with a higher percentage of clay particles is capable of holding more water than soil with less clay. This is because clay particles have a greater surface area that helps them hold water. On the other hand, soil with a higher percentage of sand particles drains water faster and is less capable of holding water. Soil with a higher percentage of silt particles falls somewhere in the middle of these two extremes.

Structure of Soil

The arrangement of particles in soil is known as soil structure. Soil structure influences the movement of water and air through soil. A well-structured soil has many large and small pore spaces that hold both water and air. A poorly-structured soil contains fewer pore spaces and is less capable of holding water.

In general, soils with a granular or crumb structure are more capable of holding water than soils with a platy, columnar, or massive structure. A granular or crumb structure has many small and large pore spaces that can hold water while still allowing air to pass through the soil. A platy, columnar, or massive structure has fewer pore spaces and is less capable of holding water.

Organic Matter Content of Soil

The organic matter content of soil refers to the amount of dead and decaying plant and animal material in the soil. Organic matter helps to hold water in soil by binding soil particles together and creating pore spaces for water to occupy. Soil with a high percentage of organic matter is usually more capable of holding water than soil with a low percentage of organic matter.

Organic matter also plays a vital role in improving soil structure. It encourages the growth of beneficial microorganisms that help to break down soil particles and create pore spaces. Furthermore, organic matter helps to reduce soil compaction, which can limit water movement within soil.

Conclusion

In conclusion, soil texture, structure, and organic matter content are the main factors that influence a soil's capacity to hold plant available water. Soil with a high percentage of clay particles, a granular or crumb structure, and a high percentage of organic matter is usually the best soil for holding water. By understanding these factors, gardeners and farmers can improve plant growth and reduce water usage by choosing the right soil for their plants.